Angle measurements are requested in many different applications. In particular in manufacturing and/or operating of mechanical devices, relative angles between different surfaces are often of vital importance. Mechanical parts having a relative motion have often to be aligned very accurately in order to ensure low wear and power consumption. Positioning of different mechanical part relative each other are also often performed by performing measurements of relative angles.
There are many approaches to angle measurements. The most straight-forward is to use mechanical means for measuring or ensuring a certain angle orientation. However, if the surfaces that are intended to be measured are sensitive for mechanical influence and/or if the space around the surfaces is limited, mechanical approaches are often difficult to perform. Furthermore, they do often involve complex assistance devices. Mechanical approaches for angle measurements are also often time consuming.
Optical means are used in prior art for angle measurements. Phenomena such as reflection, interference and diffraction are utilised. Traditional reflection measurements need highly collimated light sources, which increases cost and apparatus complexity. Interference or diffraction based methods typically need assistance parts close to the surfaces to be measured, which makes them difficult to use in applications with limited space. Furthermore, if costly parts have to be provided for each surface to be measured, the overall cost for the device becomes high.
A general problem with prior art angle measurement approaches is that they typically are time consuming, that they require complex assistance parts and/or that they are difficult to perform in limited space.